Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT01146249 |
| Other study ID # |
P070401 |
| Secondary ID |
2007-A00410-53 |
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
November 26, 2007 |
| Est. completion date |
December 18, 2020 |
Study information
| Verified date |
November 2023 |
| Source |
Assistance Publique - Hôpitaux de Paris |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Among the components of postural control, sensorial integration is of crucial importance. The
most important sensorial inputs for postural maintenance are the vestibular system which
provides information regarding accelerations of the head in space (HORAK 1994), the
somatosensory system which provides proprioceptive information that are used to determine
changes in body position (INGLIS 1994) and the visual system which provides information for
self motion in the environment. The receptors and the integration channel of each sensorial
system have inner characteristics which lead to different performance of the different input
in regards to the task and the environmental context (FITZGERALD 1994). Most of time,
sensorial information are congruent but sometimes they are conflicted. This is the case when
being in a stationary train, the train beside going on, giving the illusory sensation of
movement even if the vestibular system is not activated. A sensory weighting process is then
necessary for subjects to control balance. The Central Nervous System (CNS) is thought to
adjust the relative contribution of sensory input to control stance depending on
environmental conditions (CENCIANNI 2006) and the reliability of the sensory input (OIE 2002,
KESHNER 2004) in order to maintain or achieve the desired orientation in space and to provide
postural stability. Nevertheless the interconnection of the multiple sensorial feedback
involved in the postural control is not yet completely understood (CHIARI 2000).
Today, there is no tool available to evaluate the individual use of the sensorial information
to postural control. It seems interesting to have such a tool to better understand the
sensorial preference of subjects. It would be of particular importance for patients with
various pathologies in the aim to design individualized balance rehabilitation programs.
The aim of the study was to test a tool built to evaluate the sensorial preference of
subjects by studying their postural reaction related to the 3 main sensorial perturbations.
Normal subjects will be first tested to assess the repeatability of the protocol and to
collect normal values. Then, patients with post stroke hemiplegia, vestibular disease,
neuropathy and fallers will be studied in order to test the feasibility of the protocol and
to have preliminary data of sensorial preference among these populations.
Description:
Subjects Subjects with balance disorder related to a first hemispheric stroke, or vestibular
trouble, or neuropathy and or aging
Apparatus Balance evaluation Subjects stand barefoot on a force platform (FeeTest
Technoconcept®) consisting of two separate aluminium plates, distant of 12 cm, each placed on
2 force transducers that recorded the vertical ground reaction forces. The position of the
center of pression (COP) was calculated from the ground reaction force. The data are
collected with a sampling frequency of 40 Hz.
Sensory disturbance Sensory information (vision, proprioception and vestibular information)
are successively disturbed. For each sensory information, different perturbations are tested
in order to induce a sway in a determined direction (anterior, posterior, right and left).
Vision is disturbed by an optokinetic stimulation in a dark room, an optokinetic bowl
(OPTOTEST, Technconcept®) placed behind the subject projecting moving luminous dots on the
wall in front of the subject at the speed of 60/°s. The subjects are instructed to stare
straight ahead at the stimulus pattern without attempting to follow the moving dots. Four
trials are conducted for the visual stimulation in which the direction of the stimulus
pattern differs: the direction of the displacement of the luminous dots is first top to
bottom up, then bottom to top down, right to left and finally left to right.
Proprioceptive information is disturbed by a vibratory stimulation: vibration is delivered by
two mechanical vibrators (VB 115, TECHNOCONCEPT ®). The vibration is of 1mm amplitude and the
frequency is 50 Hz. Vibratory stimulation is first applied on the muscle tendon of the
triceps sural, afterwards on the tendon of the tibialis anterior.
Then lateral stimulation is applied with a frequency of 90 Hz on the gluteus medius.
Vestibular information Is disturbed by a galvanic stimulation: a binaural galvanic
stimulation of 2 mA is applied using a constant current stimulator (World Precision
Instruments®). Surface electrodes are placed over the mastoid processes. Four conditions are
tested: cathode placed on the right mastoid process then on the left mastoid process with the
head looking straight ahead ; cathode placed on the side of the cerebral lesion (or on the
right side for the healthy subjects), and head turned to the right then the left.
Procedure Each trial begins with a 15 second baseline period without stimulation, followed by
a 35 second period of stimulation and a final 20 second period of observation without
stimulation.
Subjects are asked to stand as steel as possible with their arms along the body looking
straight ahead (except for the last two trials of the galvanic stimulation where the head is
tilted). A trial without stimulation is registered in order to use the subject to the
procedure and for each condition sensory perturbation is tested by the subject before
starting the recording.
The subjects are tested as soon as possible after the onset of their disease and are retested
4 to 6 weeks later as they completed rehabilitation program.
Healthy subjects are also tested. Data analyzed For each sensory perturbation, we analyze two
characteristics of the behavior of the subjects during the stimulation: the displacement
induced by the stimulation and the intensity of sway during the stimulation ·Because the
position of all the subjects can not be rigorously identical among all the subjects, the
displacement induced by the stimulation is calculated by the mean of the displacement (in
millimeters)(MD) of the COP (15 to 50 seconds) in the plane of the attended effect (for
example anterior-posterior for a triceps sural trial and lateral for an optokinetic trial
from the right to the left) minus the mean position of the CoP during the prestimulation
period (2 to 13 seconds). A sensorial score is obtained in each direction for the successive
sensory stimulation. From these values, and for each sensory perturbation (visual,
proprioceptive and vestibular) a composite score is calculated as the mean of all the trials
done for one sensorial stimulation. Thus, we obtain three scores: a visual composite score, a
proprioceptive composite score and a vestibular composite score.
The number of falls induced by the stimulations is also registered.
·The intensity of sway during the stimulation is evaluated by a fast fourier transform
Statistical analysis The reproducibility of our test is assessed by the intra-class
correlation coefficient (ICC). Reproducibility is considered as correct if the ICC is
superior at 0.6 and excellent if superior at 0.8.
Descriptive data are reported as means with the (standard deviation) SDs. Correlation between
the force platform values and the subjects characteristics are evaluated by non parametric
statistics: Wilcoxon signed-rank test, Mann-Whitney test and Kruskal-Wallis test. P values
are chosen at 0.05.
